Egyptian protesters angry at a film they say insults Prophet Mohammad hurled stones on Friday at a line of police in Cairo blocking their way to the U.S. embassy, which was attacked earlier this week.

Police in riot gear fired tear gas and threw stones back at the demonstrators. A burnt-out car was overturned in the middle of the street which leads to the fortified embassy from Tahrir Square.

In Yemen, Security forces have shot live rounds in the air and fired tear gas at a crowd of around 2,000 protesters trying to march to the U.S. Embassy in the capital Sanaa.

Friday's protest comes a day after hundreds of protesters chanting "death to America" stormed the embassy compound and burned the American flag. The embassy said nobody was harmed.

In Sudan, police fired teargas on Friday to stop some 5,000 demonstrators storming the German and British embassies to protest against an anti-Islam film, a witness said. After hurling stones at the two embassies, which are next to each other in Khartoum, protesters stormed the main gates and were able to break into the German Embassy. The protesters pulled down the embassy's emblem, raised an Islamic flag, broke windows and started a fire in front of the main gate.

In Egypt, police had tried to clear the Square on Friday ahead of a nationwide protest called by the Muslim Brotherhood, Egypt's most influential group that propelled President Mohammed Morsi to power following popular protests that toppled president Hosni Mubarak and ushered in the first democratic elections in decades. But shortly after they cleared Tahrir, demonstrators returned.

The Egyptian authorities had erected large concrete blocks to block the route to the embassy.

"Before the police, we were attacked by Obama," shouted one demonstrator, blaming U.S. President Barack Obama and the U.S. government for insulting the Prophet.

One banner held aloft by demonstrators read: "It is the duty of all Muslims and Christians to kill Morris Sadek and Sam Bacile and everyone who participated in the film."

Several demonstrators waved green and black flags with Koranic verses on them.

The crowd was a mixed collection of people - some were bearded Islamists wearing traditional gallabiya robes, but most were youths and young men in T-shirts and jeans.

Egypt's president said Friday that it's up to Muslims as part of their Islamic duty to protect embassies and foreign diplomats who are guests in the country. Mohammad Morsi made the appeal on state TV on Friday, ahead of expected protests across the Muslim world over an anti-Islam film ridiculing the Prophet Muhammad.